A typical scroll machine has an orbiting scroll member which has a spiral wrap on one face thereof and a non-orbiting scroll member having a spiral wrap on one face thereof. The spiral wraps are intermeshed with one another and a mechanism is provided for causing the orbiting scroll member to orbit about an axis with respect to the non-orbiting scroll. This orbiting action will cause the wraps to create pockets of progressively decreasing volume from a suction zone to a discharge zone.
One problem associated with these scroll machines is their ability to create excessive discharge gas temperatures due to various field encountered problems. One known method of solving the problem is to cause a high-side to low-side leak of the compressed gas when these excessive temperature conditions are encountered. The prior art includes numerous systems that have been developed in response to this identified problem.
One of the primary objectives of the present invention is to provide an improved system for temperature protection. The improved system of the present invention is a simple temperature responsive valve which is simple in construction, easy to install and inspect and which improves the desired control for the compressor.
The valve of the system of the present invention improves the high pressure relief of compressed gas and hence the high temperature protection for these machines. The system of the present invention is particularly effective in scroll machines where suction gas is used to cool the motor driving the orbiting scroll member. The reason for this is because the valve will create a leak from the high side of the compressor to the low side of the compressor at conditions where discharge gas in the high side is at an elevated temperature. The leakage of this high temperature discharge gas to the suction area of the compressor causes the standard motor protector for the motor to trip and shut down the operation of the scroll machine.
The present invention therefore provides protection from excessive discharge temperature which could result from (a) loss of working fluid charge; (b) a low pressure condition or a blocked suction condition; (c) a blocked condenser fan in a refrigeration system; or (d) an excess discharge pressure condition regardless of the reason. All of these undesirable conditions will cause a scroll machine to function at a pressure ratio much greater than that which is designed into the machine in terms of its predetermined fixed volume ratio, and this will in turn cause excessive discharge temperatures.